The invention relates to an ultrasonic transducer, in particular for measuring a filling level, for example in a container, or for measuring a level, for example in a channel or on a conveyor belt.
An ultrasonic pulse emitted by the ultrasonic transducer is reflected at the surface of the filling material. The propagation time of the ultrasonic pulse from the sensor to the surface and back is determined and the filling level or the level is determined therefrom.